base64Binary

A base64Binary is arbitrary binary data in base64 encoding.

Strings consist of characters from the base64 alphabet ([0-9], [A-Z], [a-z], “+”, “/”, and “=”) with whitespace (tab, newline, carriage return, or space) allowed anywhere. Strings are padded to a multiple of four non-whitespace characters with with trailing “=” characters. For example, the base64 encoding of the string “data” is “ZGF0YQo=”.

Canonical form contains no whitespace.

size_t exess_decoded_base64_size(size_t length)

Return the maximum number of bytes required to decode length bytes of base64.

The returned value is an upper bound which is only exact for canonical strings.

Parameters:

  • length – Number of input (text) bytes to decode.

Returns:

The maximum size of a decoded value in bytes.

ExessVariableResult exess_read_base64(const char *str, size_t out_size, void *out)

Read a binary value from a base64 string.

Canonical syntax is a multiple of 4 base64 characters, with either 1 or 2 trailing “=” characters as necessary, like “Zm9vYg==”, with no whitespace. All whitespace is skipped when reading.

The caller must allocate a large enough buffer to read the value, otherwise an ExessStatus.EXESS_NO_SPACE error will be returned. The required space can be calculated with exess_decoded_base64_size().

When this is called, out must point to a buffer of at least out_size bytes. The returned result contains the exact size of the decoded data, which may be smaller than out_size. Only these first bytes are written, the rest of the buffer isn’t modified.

Parameters:

  • str – String to read.

  • out_size – Size of out in bytes.

  • out – Decoded binary data.

Returns:

The read_count of characters read, write_count of bytes written, and a status.

ExessResult exess_write_base64(size_t data_size, const void *data, size_t buf_size, char *buf)

Write a canonical base64Binary string.

The data is always written in canonical form, as a multiple of 4 characters with no whitespace and 1 or 2 trailing “=” characters as padding if necessary.

Parameters:

  • data_size – Size of data in bytes.

  • data – Data to write.

  • buf_size – Size of buf in bytes.

  • buf – Output buffer, or null to only measure.

Returns:

The count of characters in the output, and a status (ExessStatus.EXESS_SUCCESS, or ExessStatus.EXESS_NO_SPACE if the buffer is too small).